Graphite electrodes play a crucial role in various industrial processes, including steelmaking and electric arc furnace (EAF) operations. In recent years, there has been a growing demand for ultra-high power graphite electrodes that can withstand extreme temperatures and deliver optimal performance. One of the key raw materials that make this possible is needle coke, a highly engineered form of petroleum coke. Needle coke provides superior properties that enable the production of high-quality graphite electrodes capable of handling high currents and power densities. In this article, we will explore the evaluation and application of needle coke for ultra-high power graphite electrodes. We will examine needle coke impact on the performance of graphite electrodes.
We all know that the increasing output of EAF steel leads to a large increase in the demand for ultra-high power graphite electrode and its raw material needle coke. The domestic and foreign needle coke manufacturers meet the demand by putting into production, reproducing, or increasing production. But their performance is different, we put the 6 kinds of needle coke are made into electrodes respectively under the same condition, the performance of graphite electrode are compared and analyzed, and the properties are evaluated.
Coke Selection
Foreign Supplier: A, B, C, D
China Supplier: E, F
Design and Implement
Under same conditions, the 6 kinds of needle coke from different suppliers are made into UHP graphite electrode in batches.
Extruding (3,000 ton) -> First baking (850℃) -> Impregnating ->Second baking (850℃) ->Graphitization(3050℃) -> Machining
Data Analysis
Through the four-month experiment, a large amount of data was collected, and these data are now grouped into five classes and analyzed.
- Bulk Density/(g/cm3)
- Resistivity
- Modulus of Rupture
- Young’s Modulus
- CTE
Conclusions
Although these 6 needle cokes have been widely used in graphite electrode factories, their properties are different, and corresponding production process conditions must be formulated according to the test results in the production process. Needle coke A and E are most suitable to produce ultra-high power graphite electrodes. Must pay attention to the formulation of the graphitization curve of Coke A during the graphitization process to prevent the high scrap rate of the product during the graphitization process. D is not suitable to produce large-scale ultra-high power graphite electrodes, but for electrodes below Φ500mm.
Preferred priority A, E, F, B, C, D
This test is only based on needle coke from different suppliers under the same technical conditions. If the relevant conditions are changed, some indicators will change. In other words, if a certain needle coke must be used to produce ultra-high power graphite electrodes, the corresponding technical conditions should be changed to give full play to the characteristics of the raw materials. For example, when using F to produce graphite electrodes, graphitization can be appropriately reduced to achieve the purpose of optimizing its related indicators.
Since needle coke production is closely related to the performance of raw materials, this test can only determine the performance of this batch of raw materials. If the raw materials and processes of needle coke manufacturers are stable, the production of ultra-high power. You can refer to this standard when you rate graphite electrodes.
